In switching operations in electric circuits, the current flowing through a circuit is switched off when it exceeds a predetermined maximum, depending on the size of the current flowing through the circuit without resulting in a great overload current. With electronic switches, this problem is usually solved by measuring the voltage drop at a resistor as a triggering criterion, with a controller logic triggering a protective system to interrupt the circuit. Instead of a resistor, current transformers are also used. With electromagnetic circuit-breakers, an armature of a coil through which current is flowing operates on a breaker mechanism to open contacts in the conductors to be disconnected. With all such arrangements, the current may still assume a high value until disconnected due to the operating delay after a short-circuit has occurred.